Solar Image Processing at SIDC - Royal Observatory of Belgium

1. t http://sidc.be θ 1500 - V (km/s) 500 - θ Solar Image Processing at SIDC - Royal Observatory of Belgium J.-F. Hochedez, V. Delouille, S. Gissot, E. Robbrecht, B. Nicula, O. Podladchikova, J. de Patoul, D. Berghmans • In modern coronal physics, solar image processing (SIP) appears more and more as a needed and timely tool. • SIP is necessary because of: • the large sizes of the current and future missions/observatories archives, • the wish to process solar data automatically in order to evidence hidden trends (e.g. solar cycle or instrumental effects), • the need for systematic detection of rare or faint events such as EIT waves. This quest is even more acute in the context of Space Weather forecasting where quasi-real time is required. As additional benefits, the algorithmic techniques provide reproducibility and some level of objectivity. They also alleviate the effort of expert forecasters. They are sometimes able to reveal information that would remain otherwise buried in the noise or in the dynamics. Finally, they improve data representation and visualization. The necessity comes furthermore at a propitious time when the available CPU power and the underlying mathematics have developed considerably. However, the scope of SIP goes actually beyond the role of a tool. It is an integral part of our science, like visual inspection, statistical science or physics modeling. Confidence in the outcomes of any technique participates to the data analysis. In the near future and especially with AIA onboard SDO, we expect MHD modeling, SIP, statistics and data assimilation schemes to merge in one indissociable research for which certitudes involve expertise in all fields. CACTusComputer Aided CME Tracking Method:Hough transform and clustering Robbrecht and Berghmans A&A ’04 and SoPh ‘05 Result: Real-time extraction of LASCO CMEs + Catalog 1997-2004. AIA relevance:AIA-coronagraph coordinated studies Velociraptor Method: Multiscale Local Optical Flow Gissot et Hochedez A&A ’06 (in prep.) Result:Motion and ‘brightness variation’ both estimated and qualified at each pixel from local similarity & texture AIA relevance:Flares, dimmings (CMEs, EIT waves), loop motions, Dif. Rot., coronal seismology… Image and movie compression Method:recoding and MPEG4 AVC/H.264 Nicula private com + Nicula, Berghmans, Hochedez SoPh ‘05. Result:x180 compression! AIA relevance:Save Internet bandwidth! sidc.be/cactus Start time, Principal angle, Width and velocity profile Recoded pixel distortion after decompression 15h54 17h06 15h18 11 November 2003 EUV Disc segmentation Method:Fuzzy clustering Barra, Delouille, Hochedez, Chainais ’05 Proc. SPM11 Result:5 regions: AR core + AR + AR aureole + QS + CH AIA relevance:e.g. Source regions of irradiance, etc. SWB Solar Weather Browser Method:Client-Server architecture. Nicula, Berghmans, Katsiyannis, Lawrence, Baumann Result & AIA relevance:Visualisation made easy! EIT waves detector Method: Histogram skewness and kurtosis + Ring analysis. Podladchikova et Berghmans SoPh ’05 Result:Wavefront and dimming studies, 90% detection AIA relevance:EIT waves automation, coronal seismology sidc.be/SWB • Near-real-time images • Combine with overlays • Save images with overlays as PNG • Cycle through images • Dynamical interface • Simple and portable !! This is a Simple tool for easy visualisation of important Space Weather data. Synthetic Quiet Sun Method:Infinitely divisible cascades constrained by EIT histogram and fractal spectrum. in Prep Result:Artificial QS for testing algorithm (e.g. optical flow). Coronal heating relevance TBD AIA relevance:Better spatial resolution Automatic B-C-M-X Flares detection Method:Wavelet spectrum (scale measure) analysis Hochedez et al ’02 Solspa2 Proc., Delouille et al SoPh ’05 Result:Small flares automatic detection, SpW nowcast AIA relevance:Idem, continued Network scale analysis Method: Wavelet spectrum analysis Delouille et al SoPh ’05, Hochedez et al ’02 Solspa2 Proc. Result:TR network characteristic scale, cycle study AIA relevance:Continued cycle studies At flare peak 1 2 3 ½ log(μ(scale)) Just before the flare begins 1 2 3 log(scale) EIT 304 typical quiet sun Small features extraction Method:Extraction in scale space by Lipschitz coefficient Hochedez et al, ‘02, Soho11 WS, ‘03 Soho13 WS Proc. Result:BPs, brightenings and Cosmic Ray Hits extracted AIA relevance: BP studies CRH removal DC coronal heating … Loops extraction Method: Multiscale ridge detection Unpublished Expected result & AIA relevance:loop identified and labelled, DEM reconstruction, loop modeling, coronal seismology… Image enhancement Method: Normalized Contrast Transform (NCT) or Scale maps. Unpublished Expected result & AIA relevance: Preprocessing and enhance the irreplaceable visual inspection Scale map of a 195 EIT image NCT of a 195 EIT image AIA HMI Team meeting, Monterey, CA, USA, February 13-17 2006